Please cite this article in press as: Saeed, A., et al., Investigations into the effects of mass transport and flow dynamics of spacer filled membrane modules using CFD. Chem. Eng. Res. Des. (2014), http://dx.doi.org/10.1016/j.cherd.2014.07.002 ARTICLE IN PRESS CHERD-1635; No. of Pages 21 chemical engineering research and design x x x ( 2 0 1 4 ) xxx–xxx Contents lists available at ScienceDirect Chemical Engineering Research and Design j ourna l h omepage: www.elsevier.com/locate/cherd Investigations into the effects of mass transport and flow dynamics of spacer filled membrane modules using CFD Asim Saeed a , Rupa Vuthaluru b , Hari B. Vuthaluru b,∗ a Australian Centre for Energy and Process Training (ACEPT), Challenger Institute of Technology, Perth, Western Australia 6166, Australia b School of Chemical and Petroleum Engineering, Curtin University, GPO Box 1987, Perth, Western Australia 6845, Australia a b s t r a c t Cross-flow membrane operations often experience material build-up on membrane surfaces leading to maintenance issues. Although several studies addressed the flow distributions and concentration patterns during membrane operations, the prediction of fouling propensities of top and bottom membranes are non-existent. Present study investigates the effects of dimensionless filament spacing of feed spacer on flow and concentration patterns on membrane surfaces. Comparisons of spacers in terms of a novel concept ‘Spacer Configuration Efficacy’, SCE (Sh/Pn) revealed that spacers with higher SCE values would lead to higher mass transport of the solute away from the membrane walls with moderate energy losses. Among the 16 spacer arrangements studied, spacer with filament spacing of 4 was found to be the optimal (Re h up to 200) with moderate pressure drop and higher values of mass transfer coefficient for the two membrane walls, further mass transfer coefficient values for the two membrane surfaces were found to be equal which leads to equal and lower fouling tendencies of the membrane walls. © 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. Keywords: Membranes; Reverse osmosis; Mass transport; Fouling; Fluid dynamics 1. Introduction Among different types of membrane modules used for cross flow filtration processes, Spiral Wound Module (SWM) domi- nates in the area of Ultra Filtration (UF), Nano Filtration (NF) and Reverse Osmosis (RO) due to high packing density, moder- ate energy utilization, standardization, cost effectiveness and being readily available from different suppliers. However, dur- ing normal membrane separation operations material tends to build-up on the SWM membrane surfaces giving rise to many operational issues including increased energy require- ment, decline in permeate flow rate, increase in membrane resistance and eventually decrease in the membrane useful life. These issues have been addressed by several researchers, in a limited way, by proposing better pre-treatment processes (Baker et al., 1997; Wilf and Klinko, 1998; Wilf and Schierach, ∗ Corresponding author. Tel.: +61 892664685. E-mail address: h.vuthaluru@curtin.edu.au (H.B. Vuthaluru). 2001; Bonnelye et al., 2004). However, there appears to be a need to change membrane or membrane secondary structures to alter the flow patterns associated with fluids within the membrane module to combat fouling. In Spiral Wound Module (SWM) a number of flat membrane sheets are glued together, in pair arrangement, on three sides forming a pocket and a permeate spacer is introduced between the membranes pocket (Saeed et al., 2012). The fourth open end of the membrane pocket is connected to a common per- meate collector tube. The membrane pockets are rolled around the tube with feed spacers between each pocket (Fritzmann et al., 2007; Peters, 2010). As a result of the design alternating feed and permeate channels are developed. The spacer in the feed channel not only keeps the membrane layers apart, hence providing passage for the flow, but also significantly affects the flow and concentration patterns in the feed channel. They are also responsible for the pressure drop and creation of limited flow zones (dead zones) and promote mixing between the fluid bulk and fluid elements adjacent to the mem- brane surface. In other words, they are intended to keep the http://dx.doi.org/10.1016/j.cherd.2014.07.002 0263-8762/© 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.